remove origin in eip 191 prefix exemptions

use regex to match DCL message instead

Author: ethernet8023

packages/provider/src/eip191exceptions.ts

@@ -1,21 +1,35 @@
 import { ethers } from 'ethers'
 
-export function messageIsExemptFromEIP191Prefix(message: Uint8Array, origin: string | undefined): boolean {
-  return EIP_191_PREFIX_EXCEPTIONS.some(e => e.predicate(message, origin))
+export function messageIsExemptFromEIP191Prefix(message: Uint8Array): boolean {
+  return EIP_191_PREFIX_EXCEPTIONS.some(e => e.predicate(message))
 }
 
 const EIP_191_PREFIX_EXCEPTIONS: Array<{
   name: string
-  predicate: (message: Uint8Array, origin?: string) => boolean
+  predicate: (message: Uint8Array) => boolean
 }> = [
   // NOTE: Decentraland does not support 191 correctly.
-  { name: 'Decentraland Exception', predicate: (_message, origin) => origin === 'https://play.decentraland.org' },
+  {
+    name: 'Decentraland Exception',
+    predicate: isDecentralandLoginMessage
+  },
 
   // NOTE: 0x v3 does not support 191 correctly.
   // See https://gov.0x.org/t/zeip-proposal-fix-v3-eip-191-non-compliance-when-validating-eip-1271-signatures/3396 for more info.
   { name: '0x v3 Exception', predicate: isZeroExV3Order }
 ]
 
+const DCL_REGEX =
+  /^Decentraland Login\nEphemeral address: 0x[a-fA-F0-9]{40}\nExpiration: (\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2}(?:\.\d*)?)((-(\d{2}):(\d{2})|Z)?)$/
+export function isDecentralandLoginMessage(bytes: Uint8Array): boolean {
+  try {
+    const stringified = ethers.utils.toUtf8String(bytes)
+    return DCL_REGEX.test(stringified)
+  } catch {
+    return false
+  }
+}
+
 // try to interpret bytes as abi-encoded 0x v3 OrderWithHash -
 // see https://github.com/0xProject/0x-protocol-specification/blob/master/v3/v3-specification.md
 export function isZeroExV3Order(bytes: Uint8Array): boolean {

packages/provider/src/transports/wallet-request-handler.ts

@@ -300,7 +300,7 @@ export class WalletRequestHandler implements ExternalProvider, JsonRpcHandler, P
 
           // Message must be prefixed with "\x19Ethereum Signed Message:\n"
           // as defined by EIP-191
-          const prefixedMessage = prefixEIP191Message(message, this.connectOptions?.origin)
+          const prefixedMessage = prefixEIP191Message(message)
 
           // TODO:
           // if (process.env.TEST_MODE === 'true' && this.prompter === null) {

packages/provider/src/utils.ts

@@ -16,9 +16,9 @@ export const messageToBytes = (message: BytesLike): Uint8Array => {
   return ethers.utils.toUtf8Bytes(message)
 }
 
-export const prefixEIP191Message = (message: BytesLike, origin: string | undefined): Uint8Array => {
+export const prefixEIP191Message = (message: BytesLike): Uint8Array => {
   const messageBytes = messageToBytes(message)
-  if (messageIsExemptFromEIP191Prefix(messageBytes, origin)) {
+  if (messageIsExemptFromEIP191Prefix(messageBytes)) {
     return messageBytes
   } else {
     return ethers.utils.concat([eip191prefix, ethers.utils.toUtf8Bytes(String(messageBytes.length)), messageBytes])
@@ -50,7 +50,7 @@ export const isValidMessageSignature = async (
   chainId?: number,
   walletContext?: WalletContext
 ): Promise<boolean | undefined> => {
-  const prefixed = prefixEIP191Message(message, undefined)
+  const prefixed = prefixEIP191Message(message)
   const digest = encodeMessageDigest(prefixed)
   return isValidSignature(address, digest, signature, provider, chainId, walletContext)
 }

packages/provider/src/utils/index.ts

@@ -76,7 +76,7 @@ export class WalletUtils {
   ): Promise<boolean | undefined> {
     const provider = this.wallet.getProvider(chainId)
     if (!provider) throw new Error(`unable to get provider for chainId ${chainId}`)
-    const prefixed = prefixEIP191Message(message, undefined)
+    const prefixed = prefixEIP191Message(message)
     const digest = encodeMessageDigest(prefixed)
     return isValidSignature(address, digest, signature, provider, chainId, walletContext)
   }
@@ -115,7 +115,7 @@ export class WalletUtils {
     walletContext = walletContext || (await this.wallet.getWalletContext())
     return recoverWalletConfig(
       address,
-      encodeMessageDigest(prefixEIP191Message(message, undefined)),
+      encodeMessageDigest(prefixEIP191Message(message)),
       signature,
       chainId,
       walletContext

packages/provider/tests/eip191prefix.spec.ts

@@ -1,22 +1,22 @@
 import chaiAsPromised from 'chai-as-promised'
 import * as chai from 'chai'
 
-import { isZeroExV3Order, messageIsExemptFromEIP191Prefix } from '../src/eip191exceptions'
-import { message1, zeroExV3Order } from './messages'
-import { ethers } from 'ethers'
+import { messageIsExemptFromEIP191Prefix } from '../src/eip191exceptions'
+import { dclLogin, message1, zeroExV3Order } from './messages'
 const { expect } = chai.use(chaiAsPromised)
 
 describe('191 prefix exceptions', () => {
   it('decentraland is exempt', () => {
-    expect(messageIsExemptFromEIP191Prefix(message1, 'https://play.decentraland.org')).equal(true)
+    expect(messageIsExemptFromEIP191Prefix(dclLogin)).equal(true)
   })
 
   it('should strip 191 prefix from 0x v3 orders', () => {
-    expect(messageIsExemptFromEIP191Prefix(zeroExV3Order, undefined)).equal(true)
+    expect(messageIsExemptFromEIP191Prefix(zeroExV3Order)).equal(true)
   })
 
   it('should not strip 191 prefix from other messages', () => {
-    expect(messageIsExemptFromEIP191Prefix(message1, undefined)).equal(false)
-    expect(messageIsExemptFromEIP191Prefix(message1, 'https://play.example.com')).equal(false)
+    expect(messageIsExemptFromEIP191Prefix(message1)).equal(false)
+    expect(messageIsExemptFromEIP191Prefix(zeroExV3Order.slice(0, -10))).equal(false)
+    expect(messageIsExemptFromEIP191Prefix(dclLogin.slice(0, -10))).equal(false)
   })
 })

packages/provider/tests/messages.ts

@@ -1,9 +1,16 @@
+import { ethers } from "ethers"
+
 // Ethereum personal sign: Hello, World!
 export const message1 = new Uint8Array([
   25, 69, 116, 104, 101, 114, 101, 117, 109, 32, 83, 105, 103, 110, 101, 100, 32, 77, 101, 115, 115, 97, 103, 101, 58, 10, 49, 51,
   72, 101, 108, 108, 111, 44, 32, 87, 111, 114, 108, 100, 33
 ])
 
+
+export const dclLogin = ethers.utils.toUtf8Bytes(`Decentraland Login
+Ephemeral address: 0xe1bCF3CAc83534a055f7254C1FD88B21159fCc67
+Expiration: 2022-10-27T16:03:29.191Z`)
+
 // Ethereum personal sign 0x v3 order
 export const zeroExV3Order = new Uint8Array([
   62, 254, 80, 200, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 64, 3, 153, 144,